There are several situations in which the use of spill-resistant containers for fluids is desirable. One situation is a drinking cup for children. At present, there are a wide variety of spill-resistant or spill-proof drinking containers available on the market. Bottles and cups with attaching lids, both of which compel the user to suck the fluid out of the container and travel mugs, which either have a valved lid or simply a larger diameter base than top opening, all work well for their intended particular market segment. However, for daily table use by children, where a large fraction of spills occur, each of these containers has some type of deficiency. A lidded cup is naturally a bit less convenient to use than an ordinary open tumbler as the lid must be removed and replaced whenever the cup is filled. Also, the child would not be mastering the skills used to drink from an open cup with a container that requires sucking. The same problem holds true for a cup with a valved lid, which has the additional complication of coordinating valve actuation. A wide-based, open mug (Example see U.S. Pat. No. 333,067) is the simplest solution, but the mug is somewhat more difficult for a child's hand(s) to grasp than an ordinary tumbler. Also, there is the additional inconvenience that, as the mug will not nest, multiple containers consume large amounts of storage space.
Another situation is where spills, though less likely, have even more undesirable consequences. Laboratory chemical containers such as beakers, graduated cylinders, etc., which have been designed to nest to conserve storage space, suffer from the same stability concerns as drinking tumblers. However, spillage of chemicals, though infrequent, often is dangerous and/or creates a number of cleanup problems.